The present invention is directed, as indicated, to an infrared energy generator or heater with an orifice plate that impedes fuel flow through the generator plenum to cause a back pressure therein, and, more particularly, is directed to a mobile infrared energy generator capable of operation with a relatively low pressure fuel supply, such as liquid propane, while providing an infrared energy output over a relatively large area.
A conventional infrared generator or heater, which generates and radiates an infrared energy output in response to combustion of a fuel input, may include a housing, a plenum chamber or the like within the housing, a fuel input to the plenum, a fuel output from the plenum, and a radiating screen exposed to the products of the fuel combustion occuring normally between the fuel output and the screen and responsive to the thermal energy of such combustion to radiate infrared energy as an output of the infrared heater. The radiated infrared energy may be used for a variety of purposes, including, for example, indoor heating, paint drying, melting of ice outdoors, etc. Most infrared generators or heaters, especially those that are relatively large and provide their infrared energy output over a relatively large area, say forty or more square inches at the heater output, typically are supplied with a natural gas fuel input, which usually is at a relatively high pressure, say on the order of eleven inches of water, from the utility company. The relatively high pressure of the fuel allows such infrared generators to operate usually without a blow out of the flame or a backfire at the fuel input orifice to the plenum, which might be caused by a wind or other ambient atmospheric pressure or the like variation.
The fuel pressure available to an infrared generator from a mobile fuel supply, such as a liquid propane tank, is much less than the fuel pressure from a natural gas supply, often being four inches of water or less. The loweroperating pressure, then, of liquid propane supplied infrared generators would then tend to cause such infrared generators to be much more responsive to wind, drafts, pressure, or other ambient atmospheric conditions and changes, whereby blow outs or backfires would be more likely to occur. Therefore, to avoid reducing or diluting the effective fuel pressure and the sensitivity to the ambient environmental conditions, prior art mobile infrared generators supplied, for example, with vaporized or gaseous propane from a relatively mobile liquid propane fuel tank have been limited to relatively small sizes, for example, of several, usually less than four, square inches of radiating output surfaces.